Various methods and devices have been proposed for grouping and holding objects such as containers for shipping. For example, paperboard or cardboard cartons, boxes and trays, stretch wrapping and shrink wrapping, as well as combinations of the above have been employed. Various types of machines have been developed to feed, group, and package such containers.
When shrink wrapping is employed, often objects are grouped on a cardboard tray having folded up edges before applications and shrinking of the shrink film. Such trays are employed to provide stability during loading, shrink wrapping and shipment. Trays are typically rectangular, with four folded-up sides to. The edges are typically glued and/or stapled to hold them in the desired form. The articles, if all of the same type, are typically arranged in a grid on the tray. Twenty-four bottles could be arranged in a 4×6 grid on a tray, for example. Alternatively, blanks in the form of rectangular sheets of cardboard (without the folded up edges) have also been used to provide similar benefits.
Also, grouped objects can also be surrounded by one or more sheets of shrink wrap material without such trays or blanks. Typically, such shrink-wrapping requires the articles to be surrounded about their circumference by one or more pieces of film, which are then shrunk around the objects to form the package. The film typically overlaps more than 360 degrees around the objects with some overlap.
Objects to be shrink-wrapped, whether with or without trays or blanks, are fed to a wrapping zone of an apparatus already grouped. That is, the group of articles to be wrapped is separated in some way from other articles in the feed. This can be done using pin conveyors, conveyors of differing speeds, etc., to create spaces between groupings in the direction of flow so that the groupings can be individually surrounded by the film or films. Use of such equipment upstream from and within a wrapping zone can be expensive, can consume a great amount of floor space, and/or can slow a production line.
Accordingly, there remains a need for improved shrink film applying apparatus, flight bar assemblies, and methods for packaging groups of articles overcoming any of the above drawbacks or others.